Practice Exams Grade II Treatment - Division of Water Quality

233. Which of the following is not a possible cause ofshort-circuiting in a pond?A. Excessive weed growth.B. High influent BOD.C. Poor arrangement of inlet and outlet.D. Irregular pond bottom.234. Common settling times in wastewater treatment plants range fromA. 15 to 30 minutes.B. 30 to 45 minutes.C. 1 to 2 hours.D. 2 to 4 hours.235•. Which gas is produced in anaerobic digesters and can be used asa fuel?A. Propane.B. Methane.C. Ethane.D. Carbon dioxide.236. Compute the lagoon's detention time (days).DATA:Surface area = 6.0 acres.Average depth = 3.0 feet.Average evaporation exceeds precipitation by 0.4 in/day.Average daily flow (influent) = 0.25 MGD.1 acre (area) = 43,560 sq. ft.1 cu. ft. contains 7.5 gal.A. 24.B. 32.C. 37.D. None of the above.237. How many pounds of chlorine gas is necessary to treat 4,000,000gallons of wastewater at a dosage of 2 mg/L?A. 611bs.B. 65 Ibs.C. 67 Ibs.D. 69 Ibs.238. Assume a community of 1,100 people has a lagoon. The flowaverages 80,000 gallons per day. The flow isA. 14 gallons per capita.B.C.72 gallons per capita.80 gallons per capita.D. 140 gallons per capita.239. The rock in most trickling filters is placedA. Directly in the ground.B. Directly in a concrete slab.C. On a system of tile underdrains.D. On a rubber tile floor.